Engine Runs, No Forward Propulsion

[SimonSimon]

Hey guys, bought a new ski the other day but I'm having this weird issue where it doesn't want to move when given gas. It'll fire right up and Idle perfectly fine in water and moves while idling.. until applying a small amount of throttle when trying to idle out which then forward propulsion stops, losing all thrust. Literally struggles to move forward at all with any throttle but the engine sounds like it's really going (not bogging out). Kinda feels like the driveshaft is slipping? It's a 92 SN 701, impros hooker, Riva intake scoop grate, ported bottom/top end, recently rebuilt and all new gaskets. When I went to check it out it wouldn't start and the seller was fiddling around with the starter and bendix and apparently there were a few missing or loose bolts on the starter. Not sure if that is relevant but other than that and a missing flame arrestor, everything else looks solid. Still consider myself a wrench noob but learning as I go so bear with me Any help would be most appreciated or pointers on where to start first to rule out any obvious culprits before having to pull the engine lol I can post pics or videos on request.

Thanks a lot!

 

[BIG JOHNSON]

You look up through the grate?

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[SimonSimon]

What should I be looking for?

 

[khaos]

I had this problem at a freeride. Turned out I broke all 4 motor mounts and the motor slid back of the coupler. Can you rock the engine?

fwiw: Air Blair towed my broken @$$ in from about a mile out against the current through surf into the inlet.

 

[BIG JOHNSON]

What should I be looking for?

Something caught in your impeller

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[SimonSimon]

Hmm I think I would've noticed if the motor had any slop by now but I'll double check when I get home and also check for any obstructions in the impeller. I'll keep you guys updated thanks.

 

[mike b]

Ive ran into issues with worn splines, pump housing veins, and impellers. Check with a light that the impeller looks like it is in good shape and then check the veins on the pump housing to make sure that they are not chipped a bunch and missing material. If not that stuff then grab your wrench and remove the pump to check the splines on the shaft. Id put money on pump housing/impeller eating a rock or something stuck inside causing it to spin but not give you any thrust. GOOD LUCK

 

[cookn]

im thinking stripped driveshaft as well, probably just enough spline left to turn the prop at idle but spins in the midshaft when throttle is applied. And a side note any missing bolts on your ski in not good, I would find some replacements before there is a starter problem, its your life line and oem starters are not cheap

 

[SimonSimon]

I removed the grate and plate and everything seems normal. Impeller checks out.. no obstructions and pump housing looks to be in good shape. I attached some pics. I guess next step will be pulling the pump and inspecting driveshaft/midshaft splines for wear.
Side note: That problem I initially mentioned about the starter (bendix is not engaging) seems to be back again. The sound of it makes me want to gnash my teeth. I took a quick video:

 

[SimonSimon]

So I pulled the pump and the driveshaft splines look good. However the pump seal is nowhere to be found! Yikes..

 

[Kohldanielzimmer]

how are the splines on the midshaft?

 

[Kohldanielzimmer]

looks like someone gooped it with black silicone of 5200 instead of using a seal... With massive cavitation you could see a substantial loss of propulsion but I still think you'd have some forward movement.

 

[cookn]

thats exactly the problem, get a pump seal in there and it should work

 

[SimonSimon]

I do have a little bit of forward movement but not much after idling out. And it's hard to tell how midshaft looks without pulling the motor. I think they look decent peeking at it with a flashlight.

 

[SimonSimon]

Yup will do. Gonna stop by my local marine shop and see if they have any in stock. In the meantime I gotta fix this damn starter issue now :/

 

[Kohldanielzimmer]

I think you've likely found the culprit. Happy sailing.

 

[SimonSimon]

Dang I gotta wait a week for them to order the part. Could I just silicone it in the mean time to get some riding time in? And what kind of silicone is recommended? Thanks

 

[Vumad]

Dang I gotta wait a week for them to order the part. Could I just silicone it in the mean time to get some riding time in? And what kind of silicone is recommended? Thanks

650 kawi pumps are sealed to the hull with silicone. 100% silicone 2 at your local hardware store. Don't get the silicone blends. The one you want says 100% silicone. Should last the week but takes a minimum of 24 hours to dry. Easiest way to remove it when you are done with it is to take it almost off with a scraper and then clean it up with a wire brush. For the hassle, I'd just wait for it to arrive. Next time just order from @JetManiac and pay the extra for fast shipping. Pretty sure the guy has a time machine to get his orders out. I think once I had a package arrive with the parts I needed the day before I actually ordered them.

 

[SimonSimon]

650 kawi pumps are sealed to the hull with silicone. 100% silicone 2 at your local hardware store. Don't get the silicone blends. The one you want says 100% silicone. Should last the week but takes a minimum of 24 hours to dry. Easiest way to remove it when you are done with it is to take it almost off with a scraper and then clean it up with a wire brush. For the hassle, I'd just wait for it to arrive. Next time just order from @JetManiac and pay the extra for fast shipping. Pretty sure the guy has a time machine to get his orders out. I think once I had a package arrive with the parts I needed the day before I actually ordered them.

lol Well I called them and canceled the order. I'm gonna order from JetManiac with expedited shipping. Thanks!

 

[SimonSimon]

Just for s**ts and giggles, would this silicone work? Got some spare laying around the house. It even says water ready in 3 hours! Haha